Tube structure



H. NICLASSEN TUBE STRUCTURE Feb. 2z, 1938.

Filed Nov. 19, 1935 INVENTOR l HANS NICLASSEN SYM Q /lav-M/ ATTORNEY Patented Feb. 22, 1938 UNITED STATES PATENT OFFICE TUBE STRUCTURE ven, Netherlands Application November 19, 1935, Serial No. 50,487

In Germany November 12, 1934 4 Claims.

The inlet of electric conductors into an electric discharge vessel is usually eiected through a glass press stem which after the sealing-in operation is surrounded by a cylindrical or conical 5 part of the vessel wall. Since the glass at the sealing point always underlies internal stresses it may readily crack. Once a crack occurs it very often proceeds on roundabout so that the press stem is detached from the remaining vessel. In this lo case a sudden Very violent pressure equalization, a so-called implosion, often occurs between the vacuum space and the open air. The initial pressure difference forcibly pushes the press stem into the interior of the vessel, thus causing rupture of the thin supply conductors. The press stem almost immediately attains a high speed so that it may crash the opposite vessel wall and penetrates through it into the surrounding space.

Particularly with oscillograph-tubes this involves a risk for the persons operating or observing the tube, since in such tubes the vessel wall which lies opposite the seal and carries the luminous layer is very thin. As is well known oscillograph tubes are also used for television exhibitions and in this case the persons stay closely in front of the luminous screen. In order to protect them it has already been proposed to lodge such tubes in a completely closed housing which comprises a thick splinter-proof glass disc in front of the luminous screen. However, this solution of avoiding the above risk is comparatively expensive, .and at the same time it involves a weakening of the picture impressions received by the spectator.

The present invention provides a simple means for eliminating the risk of implosion with discharge tubes, thus allowing of dispensing with the protecting disc in oscillograph tubes and rendering the installation simpler and more powerful. The idea underlying the invention consists in that penetration of the opposite vessel wall by the press stern severed from the remaining vessel is avoided. For this purpose at least one metal piece, for instance a wire, is

sealed into the press stem, said piece being secured to a part outside the discharge vessel, for instance to a portion of the cap or of the housing, and having such a strength that it does not break under the influence of the efforts ensuing in the case of an implosion. The metal piece might also be secured in a suitable manner to the wall of the bulb.

'I'he metal piece may consist of the same material as is used for the supply conductors and (Cl. Z50-27.5)

be constituted, for instance, by a copper sheath wire. In this case, however, it should be stronger than the usual sealingein wires and have a strength of about 800 pounds per square inch or even more. However, it may also consist of another material chosen only in respect of rnechanical strength and good sealing properties to glass, without considering its electrical properties, and having such a strength that a wire of the hitherto usual thickness for instance 400 pounds per square inch, for supply wires satises the required condition.

The invention has been illustrated schematically by the accompanying drawing, which shows one suitable form of the device.

Fig. 1 is a sectional view of the lower portion of a cathode ray tube showing the mounting of the gun structure in the lower end of the tube, and

Fig. 2 is a sectional View on the line 2--2 of Fig. 1, but at right angles to the plane of the paper as Fig. l is shown, it being noted that in Fig. 2 the electrode structure of Fig. l is omitted and also the support base member.

Fig. 3 is a view similar to that oi Fig. 2 illustrating a modiiied form of the invention.

Referring now to the drawing for a further description of this invention, the invention will be assumed to be applied to a cathode ray tube, although this application is only one of a plurality of uses. In the form in which the invention has been shown, into the lower end of the cylindrical member I of the tube there is positioned at the time of evacuation the stem structure 3 which supports the various electrode elements. Through the stem structure 3 the various conductor elements 5 connecting to all or several electrodes are passed. At the point where the conductor members 5 pass through the stem, the usual press 1 is formed so as to anchor the support wires for the electrode structure rigidly within the tube. The upper conductor members 9, II, I3 and I5 which supply the voltages to the various electrode members of the tube are suitably welded to the lead in Wires 5 at the points II according to known practice. The con ductor members i3 and I5 are arranged to supply heating current to the heater element I9 mounted inside of the cathode member 2l. The upper end of the cathode member 2| has a suitable electron emitting material 23 carried in the upper end thereof. This material may occupy either substantially the entire area of the cathode or may be restricted to a minute portion thereof.

The control grid member is formed in the nature of a sleeve 25 and is suitably attached to the grid control wire ll at the point 21. The electrons emitted from the cathode emitter 23 pass through the aperture in the grid structure. The anode member 29 is also formed from a cylindrical sleeve and has provided therein suitable apertures 3| through which the emitted electrons pass. The anode and grid cylinders are suitably spaced one from the other by means of insulator spacer members 33 and are rigidly mounted in longitudinally spaced relationship by means of a glass bead 35 separating the support rods or Wires 3l, 34 which are suitably arranged about the periphery of the two cylinders at convenient locations.

It has been found that in tubes of the highly evacuated type, frequently, due to implosions, the complete electrode structure, as well as the stem, tends to break away from the lower end of the tubular sleeve, forming the outer Wall of the tube. Thus, there is av tendency to rupture the entire container and assembly. In or-der to avoid these difficulties, according to the present invention, provision is made for securely anchoring the stem and electrode structure to a portion of the tube wall or to the supporting base thereof, the entire stem press and electrode structure. This is provided by means of a heavy conductor member 39 which passes through the press and which has no welds therein. TheI wire or rod 39 in the form in which the invention is shown, is arranged to pass outwardly through the wall i of the tube and is anchored at 4l by any suitable anchoring, by means of a cap or the like.

While the invention, as illustrated, shows the anchoring rod or Wire 39 securedl to the tube wall, of course, it is obvious that by extending the support base member 43 slightly upward fro-m that position in which it is shown, the anchoring wire or rod 39 may be secured still more rigidly to the support base itself. As is the custom with the usual tubes, the support base 43 has pro-A vided in the lower portion thereof, suitable pins 45 to which the conducting leads 5 are attached and the pins may then be supported in any usual mounting socket. As in usual practice, the stem structure is sealed to the tube wall at the sealing point 47.

Many other forms of the invention may be a-dopted Without departing from the spirit and scope thereof, and it further may be remarked that it may be advantageous completely to retain the wires hitherto used for the supply of current, but to seal-in, moreover, a metal piece according to the invention, this piece affording only protection against implosion. One or more supply conductors sealed into the pinch stem may be used at the same time as a protection and be formed accordingly. A particular advantageous form of construction of the invention is obtained if the metal piece which serves as a protection has no weld point inside the pinch.

Having now described the invention, what is claimed is:

l.. An electron discharge tube comprising electrodes, an envelope, a press, an anchoring member passing through said press transversely to the major axis thereof, and means fastening said anchoring member to the walls of said envelope.

2. An electron discharge tube comprising electrodes, an envelope, a supporting base member for said envelope, a press, an anchoring member passing through said press transversely to the major axis thereof, and means fastening said anchoring member to the aforesaid supporting base.

3. An electron discharge tube comprising electrodes, a press, a plurality of anchoring members passing through said press transversely to the major axis thereof and mounted at an angle to each other, and means fastening said anchoring members to the walls of said envelope.

4. An electron discharge tube comprising electrodes, an envelope, a supporting base member for said envelope, a press anchoring a plurality of anchoring members -passing through said press transversely to the major axis thereof and mounted at an angle to each other, and means fastening said anchoring members to the aforesaid supporting base member.

HANS NICLASSEN. 

